Lithium thermal conductivity

The next step in this study is to test this control algorithm on the actual laboratory reactor. The major difficulty is the direct measurement of the state variables in the reactor (T, M, I, W). Proposed strategy is to measure total mols of polymer (T) with visible light absorption and monomer concentration (M) with IR absorption. Initiator concentration (I) can be monitored by titrating the n-butyl lithium with water and detecting the resultant butane gas in a thermal conductivity cell. Finally W can be obtained by refractive index measurements in conjuction with the other three measurements. Preliminary experiments indicate that this strategy will result in fast and accurate measurements of the state vector x. 

Potassium and sodium are good conductors of heat.23 If the conductivity of silver be unity, that of sodium is 0 365. J. W. Hornbeck found the temp, coeff. of the thermal conductivity of potassium or sodium falls with rise of temp. The alkali metals are also good conductors of electricity 24 for example, the conductivity of sodium for heat and electricity is exceeded only by silver, copper, and gold. According to E. F. Northrup, the metals sodium, potassium, mercury, tin, lead, and bismuth have the same value for the ratio of the coeff. of electrical resistance to the coeff. of cubical expansion at the same temp. The electrical conductivity of lithium is nearly ll-4xl04 reciprocal ohms at 20°, that is, about 20 4 per cent, of the conductivity of hard silver of sodium at 2T 70, 22 4 XlO4 reciprocal ohms, that is, about 36 5 per cent, of the value of silver. 

Lithium and its compounds may be used in fusion reactors in either liquid or solid form. Liquid Li is an excellent coolant with low density and viscosity, and with high heat capacity and thermal conductivity (Table 1). Consequently, it is used in many designs as a combined breeding material and coolant. However, hot molten Li can react violently with water or air under certain conditions. Hence, either strict engineering design must preclude large scale Li - air or water reactions, or another form of Li must be used. Both approaches have been studied. 

Abrahams, I. and Hadzifejzovic, E., Lithium ion conductivity and thermal behaviour of glasses and crystallised glasses in the system Li20-Al203-Ti02-P205, Solid State Ionics, 134, 249, 2000. 

Molten lithium metal is a potential candidate for the coolant to be circulated through the blanket. Lithium is a light metal with a low melting point (186 degrees Celsius). In the liquid state, it has a high specific heat and thermal conductivity. These properties make it an excellent heat transfer material and thus, a good choice as a means of removing heat from the reactor. When lithium is used in the blanket for heat transfer it also serves as the primary absorber of the 14,100 keV neutrons from the D + T reaction. 

Some of the most important properties of sodium and lithium for high-temperature nuclear-reactor applications are listed in Table I. Several other popular and potential heat-transfer fluids are shown for comparison purposes. The advantages and disadvantages of various coolants are considered in relation to their application at temperatures in excess of 1200 °F. The undesirable properties of a particular coolant are underlined. Water is not particularly suitable because of its very low boiling point and its poor thermal conductivity. Sodium and the sodium-potassium alloy have properties to which there are no major objections. (Any statement made in this paper concerning the corrosiveness of sodium may be considered as applicable to the sodium-potassium alloys, as differences found... 

Although there are many unknown or uncertain factors related to the fundamental nature of nanocomposites (nanotube greases), the increased electrical and thermal conductivities by addition of nanofillers strongly indicate that these nanotube greases could replace the current commercial greases (lithium, calcium, aluminum, and polyurea) and have a promising future in commercial applications. 

A major factor in the reduced safety of lithium-ion batteries is their design. The temperature of a cell is determined by the balance between the amount of heat generation and dissipation. Obviously, the heat balance depends on the thermal capacity of the cell, as well as the thermal conductivity, emissivity, external surface area and geometry of the cell. At temperatures above 130-150°C, exothermic chemical reactions between the electrodes and electrolyte set in, which further raise the temperature of the cell. Any cell design that cannot dissipate this heat will promote exothermic reactions inside the cell under adiabatic-like conditions, which can rapidly... 

The calculated viscosity, thermal conductivity and self-diffusion coefficients (the latter at 0.10 MPa) of nonionized monatomic lithium, sodium, potassium, rubidium and cesium vapors can be consulted for temperatures between 700 and 2000 K in Tables VIII to XII of the work of Fialho et al. (1993). 

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